Phio Pharmaceuticals (PHIO) 10-K 30 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Mar. 30, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	RXII
Entity Registrant Name	RXi Pharmaceuticals Corp
Entity Central Index Key	1533040
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		31,221,598
Entity Public Float			$37,709,309

Balance_Sheets

Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$8,496	$11,390
Restricted cash	50	50
Short-term investments		3,000
Prepaid expenses and other current assets	442	303
Total current assets	8,988	14,743
Equipment and furnishings, net of accumulated depreciation of $702 and $632, in 2014 and 2013, respectively	183	177
Other assets	18	18
Total assets	9,189	14,938
Current liabilities:
Accounts payable	285	163
Accrued expenses and other current liabilities	1,002	1,795
Deferred revenue	47	118
Total current liabilities	1,334	2,076
Commitments and contingencies (Note 6)
Stockholders' equity (Note 8):
Preferred stock	0	0
Common stock, $0.0001 par value, 100,000,000 shares authorized; 21,984,272 and 11,788,045 shares issued and outstanding at December 31, 2014 and 2013, respectively	2	1
Additional paid-in capital	48,047	40,969
Accumulated deficit	-46,882	-38,082
Total stockholders' equity	2,745	4,942
Total liabilities, convertible preferred stock and stockholders' equity	9,189	14,938
Series A Convertible Preferred Stock [Member]
Convertible preferred stock (Note 7):
Series A convertible preferred stock, $0.0001 par value, 15,000 shares authorized; 5,110 and 7,920 shares issued and outstanding at December 31, 2014 and 2013, respectively (at liquidation value)	5,110	7,920
Series A-1 Convertible Preferred Stock [Member]
Stockholders' equity (Note 8):
Preferred stock	1,578	2,054
Total stockholders' equity	$1,578	$2,054

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Accumulated depreciation	$702	$632
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	21,984,272	21,984,272
Common stock, shares outstanding	11,788,045	11,788,045
Series A Convertible Preferred Stock [Member]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	15,000	15,000
Preferred stock, shares issued	5,110	7,920
Preferred stock, shares outstanding	5,110	7,920
Series A-1 Convertible Preferred Stock [Member]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	1,578	1,578
Preferred stock, shares outstanding	2,054	2,054

Statement_of_Operations

Statement of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Revenues:
Grant revenues	$71		$399
Operating Expenses:
Research and development expenses	5,680	[1]	17,651	[1]
General and administrative expenses	3,217	[1]	3,697	[1]
Total operating expenses	8,897		21,348
Operating loss	-8,826		-20,949
Interest income, net	17		24
Other income, net	9
Loss from continuing operations before income taxes	-8,800		-20,925
Provision for income taxes	0		0
Net loss	-8,800		-20,925
Series A and A-1 convertible preferred stock dividends	-4,130		-8,610
Net loss applicable to common stockholders	($12,930)		($29,535)
Net loss per common share applicable to common stockholders (Note 2):
Basic and diluted	($0.79)		($2.88)
Weighted average common shares: basic and diluted	16,362,905		10,263,954
[1]	Non-cash stock-based compensation expenses included in operating expenses are as follows: Research and development 632 912 532 General and administrative 770 1,067 436

Statement_of_Operations_Parent

Statement of Operations (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Research and Development Expense [Member]
Non-cash stock-based compensation expenses	$836	$912
General and Administrative Expense [Member]
Non-cash stock-based compensation expenses	$1,010	$1,067

Statements_of_Convertible_Pref

Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (USD $)	Total	Series A Convertible Preferred Stock [Member]	Series A-1 Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
In Thousands, except Share data
Series A convertible preferred stock, Beginning balance at Dec. 31, 2012		$9,726
Beginning balance at Dec. 31, 2012	-5,840				11,317	-17,157
Series A convertible preferred stock, Beginning balance, shares at Dec. 31, 2012		9,726
Beginning balance, shares at Dec. 31, 2012				5,289,007
Issuance of common stock, net of offering costs of $114	15,651			1	15,650
Issuance of common stock, net of offering costs of $114, shares				3,765,230
Issuance of common stock in exchange for patent and technology rights	12,250				12,250
Issuance of common stock in exchange for patent and technology rights, Shares				1,666,666
Stock-based compensation expense	1,979				1,979
Cash paid in lieu of fractional shares for 1:30 reverse stock split	-12				-12
Cash paid in lieu of fractional shares for 1:30 reverse stock split, shares				-2,807
Common stock issued upon exercise of stock options	5				5
Common stock issued upon exercise of stock options, shares				2,000
Issuance of common stock under employee stock purchase plan	28				28
Issuance of common stock under employee stock purchase plan, shares				11,265
Exchange of Series A convertible preferred stock into Series A-1 convertible preferred stock	2,000	-2,000	2,000
Exchange of Series A convertible preferred stock into Series A-1 convertible preferred stock, shares		-2,000	2,000
Conversions of Series A and Series A-1 convertible preferred stock into common stock	434	-434			434
Conversions of Series A and Series A-1 convertible preferred stock into common stock, shares		-434		1,056,684
Fair value of Series A and Series A-1 convertible preferred stock dividends	-8,610				-8,610
Dividends issued on Series A and Series A-1 convertible preferred stock	7,982	628	54		7,928
Dividends issued on Series A and Series A-1 convertible preferred stock, shares		628	54
Net loss	-20,925					-20,925
Series A convertible preferred stock, Ending balance at Dec. 31, 2013		7,920
Ending balance at Dec. 31, 2013	4,942		2,054	1	40,969	-38,082
Series A convertible preferred stock, Ending balance, shares at Dec. 31, 2013		7,920
Ending balance, shares at Dec. 31, 2013			2,054	11,788,045
Issuance of common stock, net of offering costs of $114	1,886				1,886
Issuance of common stock, net of offering costs of $114, shares				700,000
Stock-based compensation expense	1,846				1,846
Common stock issued upon exercise of stock options, shares	0
Issuance of common stock under employee stock purchase plan	61				61
Issuance of common stock under employee stock purchase plan, shares				32,515
Exchange of Series A convertible preferred stock into Series A-1 convertible preferred stock	3,000	-3,000	3,000
Exchange of Series A convertible preferred stock into Series A-1 convertible preferred stock, shares		-3,000	3,000
Conversions of Series A and Series A-1 convertible preferred stock into common stock	166	-166	-3,716	1	3,881
Conversions of Series A and Series A-1 convertible preferred stock into common stock, shares		-166	-3,716	9,463,712
Fair value of Series A and Series A-1 convertible preferred stock dividends	-4,130				-4,130
Dividends issued on Series A and Series A-1 convertible preferred stock	3,774	356	240		3,534
Dividends issued on Series A and Series A-1 convertible preferred stock, shares		356	240
Net loss	-8,800					-8,800
Series A convertible preferred stock, Ending balance at Dec. 31, 2014		5,110
Ending balance at Dec. 31, 2014	$2,745		$1,578	$2	$48,047	($46,882)
Series A convertible preferred stock, Ending balance, shares at Dec. 31, 2014		5,110
Ending balance, shares at Dec. 31, 2014			1,578	21,984,272

Statements_of_Convertible_Pref1

Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Offering costs	$114	$727
Reverse Stock Split Conversion Ratio		0.033
Common Stock [Member]
Offering costs	$114	$727

Statement_of_Cash_Flows

Statement of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net loss	($8,800)	($20,925)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	87	99
Gain on disposal of equipment	-10
Non-cash share-based compensation expense	1,846	1,979
Fair value of common stock issued in exchange for patent and technology rights		12,250
Changes in operating assets and liabilities:
Prepaid expenses and other assets	-139	-89
Accounts payable	122	-253
Accrued expenses and other current liabilities	-793	1,028
Deferred revenue	-71	-400
Net cash used in operating activities	-7,758	-6,311
Cash flows from investing activities:
Change in restricted cash		3
Purchase of short-term investments	-5,000	-9,000
Maturities of short-term investments	8,000	6,000
Cash paid for purchase of equipment and furnishings	-95	-78
Proceeds from disposal of equipment and furnishings	12
Cash paid for lease deposit		-18
Net cash provided by (used in)investing activities	2,917	-3,093
Cash flows from financing activities:
Net proceeds from the issuance of common stock	1,886	15,651
Proceeds from exercise of stock options		5
Proceeds from issuance of common stock in connection with employee stock purchase plan	61	28
Cash paid in lieu of fractional shares for 1:30 reverse stock split		-12
Repayments of capital lease obligations		-5
Net cash provided by financing activities	1,947	15,667
Net (decrease) increase in cash and cash equivalents	-2,894	6,263
Cash and cash equivalents at the beginning of period	11,390	5,127
Cash and cash equivalents at the end of period	8,496	11,390
Supplemental disclosure of non-cash investing and financing activities:
Exchange of Series A convertible preferred stock into Series A-1 convertible preferred stock	3,000	2,000
Conversion of Series A and Series A-1 convertible preferred stock into common stock	3,882	434
Fair value of Series A and Series A-1 convertible preferred stock dividends	4,130	8,610
Series A and Series A-1 convertible preferred stock dividends	$596	$682

Statement_of_Cash_Flows_Parent

Statement of Cash Flows (Parenthetical)	12 Months Ended
	Dec. 31, 2013
Statement of Cash Flows [Abstract]
Reverse stock split ratio	0.033

Nature_of_Business

Nature of Business	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Nature of Business	1. Nature of Business
	RXi Pharmaceuticals Corporation (“RXi,” “we,” “our” or the “Company”) is a biotechnology company focused on discovering and developing innovative therapies addressing high unmet medical needs, primarily in the areas of dermatology and ophthalmology. Our development programs are based on our siRNA technology and immunotherapy agents. Our clinical development programs include, but are not limited to, our proprietary, self-delivering RNAi (sd-rxRNA®) compounds for the treatment of dermal and retinal scarring and an immunodulating agent, Samcyprone™, for the treatment of such disorders as alopecia areata, warts and cutaneous metastases of melanoma. In addition to these clinical programs, we have a pipeline of discovery and preclinical product candidates in our core therapeutic areas, as well as in other areas of interest. The Company’s pipeline, coupled with our extensive patent portfolio, provides for the advancement to further discover and develop innovative therapies either on our own or in collaboration with strategic partners.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies
	Basis of Presentation — The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”).
	Uses of Estimates in Preparation of Financial Statements — The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from these estimates.
	Cash and Cash Equivalents — The Company considers all highly liquid debt instruments with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts and certificates of deposit.
	Restricted Cash — Restricted cash consists of certificates of deposit held by financial institutions as collateral for the Company’s corporate credit cards.
	Short-term Investments — The Company’s short-term investments consist of certificates of deposit with original maturities ranging from three months to one year.
	Concentrations of Credit Risk — Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents and short-term investments. The Company maintains cash balances in several accounts with one bank, which at times are in excess of federally insured limits. The Company has established guidelines related to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company’s investments are maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the exposure of any single issuer.
	Fair Value of Financial Instruments — The carrying amounts reported in the balance sheet for cash equivalents, restricted cash, short-term investments and accounts payable approximate their fair values due to their short-term nature or market rates of interest.
	Equipment and Furnishings — Equipment and furnishings are stated at cost and depreciated using the straight-line method based on the estimated useful lives of the related assets. The Company provides for depreciation over the assets’ estimated useful lives as follows:
	Computer equipment		3 years
	Machinery & equipment		5 years
	Office furniture		5 years
	Depreciation and amortization expense for the years ended December 31, 2014 and 2013 was approximately $87,000 and $99,000, respectively.
	Impairment of Long-Lived Assets — The Company reviews long-lived assets for impairment on an annual basis, as of December 31, or on an interim basis if an event occurs that might reduce the fair value of such assets below their carrying values. An impairment loss would be recognized based on the difference between the carrying value of the asset and its estimated fair value, which would be determined based on either discounted future cash flows or other appropriate fair value methods. The Company believes no impairment existed as of December 31, 2014 and 2013.
	Revenue Recognition — The Company recognizes revenue when all of the following criteria are met: there is persuasive evidence of an arrangement, the fee is fixed or determinable, delivery has occurred or services have been rendered and collection of the related receivable is reasonably assured. The Company may generate revenue from product sales, license agreements, collaborative research and development arrangements, and government grants. To date the Company’s principal source of revenue consists of government research grants. Revenue from a government grant is recognized over the respective contract periods as the services are performed. Monies received prior to the recognition of revenue are recorded as deferred revenue.
	Stock-based Compensation — The Company follows the provisions of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 718, “Compensation – Stock Compensation” (“ASC 718”) which requires the measurement and recognition of compensation expense for all stock-based payment awards made to employees, officers and non-employee directors, including stock options. Stock compensation expense based on the grant date fair value estimated in accordance with the provisions of ASC 718 is recognized as an expense over the requisite service period.
	For stock options granted as consideration for services rendered by non-employees, the Company recognizes compensation expense in accordance with the requirements of FASB ASC Topic 505-50, “Equity Based Payments to Non-Employees.” Non-employee option grants that do not vest immediately upon grant are recorded as an expense over the requisite service period of the underlying stock options. At the end of each financial reporting period prior to vesting, the value of these options, as calculated using the Black-Scholes option-pricing model, will be re-measured using the fair value of the Company’s common stock and the non-cash compensation recognized during the period will be adjusted accordingly. Since the fair market value of options granted to non-employees is subject to change in the future, the amount of the future compensation expense will include fair value re-measurements until the stock options are fully vested.
	Research and Development Expenses — Research and development costs are charged to expense as incurred and relate to salaries, employee benefits, facility-related expenses, supplies, share-based compensation related to employees and non-employees involved in the Company’s research and development, external services, other operating costs and overhead related to our research and development departments, costs to acquire technology licenses and expenses associated with preclinical activities and our clinical trials. Payments made by the Company in advance for research and development services not yet provided and/or for materials not yet received are recorded as prepaid expenses. Accrued liabilities are recorded related to those expenses for which vendors have not yet billed us with respect to services provided and/or materials that we have received.
	Preclinical and clinical trial expenses relate to third-party services, subject-related fees at the sites where our clinical trials are being conducted, laboratory costs, analysis costs, toxicology studies and investigator fees. Costs associated with these expenses are generally payable on the passage of time or when certain milestones are achieved. Expense is recorded during the period incurred or in the period in which a milestone is achieved. In order to ensure that we have adequately provided for preclinical and clinical expenses during the proper period, we maintain an accrual to cover these expenses. These accruals are assessed on a quarterly basis and are based on such assumptions as expected total cost, the number of subjects and clinical trial sites and length of the study. Actual results may differ from these estimates and could have a material impact on our reported results. Our historical accrual estimates have not been materially different from our actual costs.
	Patents and Patent Application Costs — Although the Company believes that its patents and underlying technology have continuing value, the amount of future benefits to be derived from the patents is uncertain. Patent costs are, therefore, expensed as incurred.
	Income Taxes — The Company recognizes assets or liabilities for the deferred tax consequences of temporary differences between the tax basis of assets or liabilities and their reported amounts in the financial statements in accordance with FASB ASC 740, “Accounting for Income Taxes” (“ASC 740”). These temporary differences will result in taxable or deductible amounts in future years when the reported amounts of the assets or liabilities are recovered or settled. ASC 740 requires that a valuation allowance be established when management determines that it is more likely than not that all or a portion of a deferred asset will not be realized. The Company evaluates the realizability of its net deferred income tax assets and valuation allowances as necessary, at least on an annual basis. During this evaluation, the Company reviews its forecasts of income in conjunction with other positive and negative evidence surrounding the realizability of its deferred income tax assets to determine if a valuation allowance is required. Adjustments to the valuation allowance will increase or decrease the Company’s income tax provision or benefit. The recognition and measurement of benefits related to the Company’s tax positions requires significant judgment, as uncertainties often exist with respect to new laws, new interpretations of existing laws, and rulings by taxing authorities. Differences between actual results and the Company’s assumptions or changes in the Company’s assumptions in future periods are recorded in the period they become known.
	Comprehensive Loss — The Company’s comprehensive loss is equal to its net loss for all periods presented.
	Net Loss per Share — The Company accounts for and discloses net loss per common share in accordance with FASB ASC Topic 260, “Earnings per Share.” Basic and diluted net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted average number of common shares outstanding. When the effects are not anti-dilutive, diluted earnings per share is computed by dividing the Company’s net earnings by the weighted average number of common shares outstanding and the impact of all dilutive potential common shares.
	The following table sets forth the potential common shares excluded from the calculation of net loss per common share because their inclusion would be anti-dilutive:
		December 31,
		2014		2013
	Options to purchase common stock		3,000,264		2,556,269
	Common stock underlying Series A and Series A-1 convertible preferred stock		16,300,969		24,313,108
	Warrants to purchase common stock		4,615		4,615
	Total		19,305,848		26,873,992

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	3. Recent Accounting Pronouncements
	In August 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-15, Presentation of Financial Statements — Going Concern (Topic 915): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 states that in connection with preparing financial statements for each annual and interim reporting period, an entity’s management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). ASU 2014-15 will be effective for annual and interim periods beginning on or after December 15, 2016, and will be effective for the Company beginning on January 1, 2017. Early adoption is permitted. The Company is currently evaluating the impact, if any, of the adoption of this update.
	In June 2014, the FASB issued ASU 2014-10, “Development Stage Entities (Topic 915) — Elimination of Certain Financial Reporting Requirements, Including an Amendment to Variable Interest Entities Guidance in Topic 810, Consolidation.” ASU 2014-10 eliminates the concept of a development-stage entity in its entirety from current accounting guidance. Under current guidance, development-stage entities are required to present inception-to-date financial information in their annual statements. The new standard eliminates the concept of a development-stage entity from generally accepted accounting principles. Therefore, the current incremental reporting requirements for a development-stage entity, including inception-to-date information, will no longer apply. The new standard is effective for reporting periods beginning on or after December 15, 2014, and interim periods therein. The Company adopted this standard in June 2014. Other than the exclusion of the presentation of inception-to-date financial information, the adoption of this standard did not have a material impact on the Company’s financial statements.
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 states that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new standard will be effective for annual and interim periods beginning on or after December 15, 2016, and will be effective for the Company beginning on January 1, 2017. Early adoption is not permitted. The Company is currently evaluating the method of adoption and the potential impact the update may have on our financial position and results of operations.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements
	The Company follows the provisions of FASB ASC Topic 820, “Fair Value Measurements and Disclosures,” for the Company’s financial assets and liabilities that are re-measured and reported at fair value at each reporting period and are re-measured and reported at fair value at least annually using a fair value hierarchy that is broken down into three levels. Level inputs are as defined as follows:
	Level 1 —	quoted prices in active markets for identical assets or liabilities.
	Level 2 —	other significant observable inputs for the assets or liabilities through corroboration with market data at the measurement date.
	Level 3 —	significant unobservable inputs that reflect management’s best estimate of what market participants would use to price the assets or liabilities at the measurement date.
	The Company categorized its cash equivalents, restricted cash and short-term investments as Level 2 hierarchy. The assets classified as Level 2 have initially been valued at transaction price and subsequently valued, at the end of each reporting period, using other market observable data. Observable market data points include quoted prices, interest rates, reportable trades and other industry and economic events. Financial assets measured at fair value on a recurring basis are summarized as follows, in thousands:
	Description	December 31,		Quoted Prices in		Significant Other		Unobservable Inputs
		2014		Active Markets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	Assets:
	Cash equivalents	$	4,000	$	—	$	4,000	$	—
	Restricted cash		50		—		50		—
	Total	$	4,050	$	—	$	4,050	$	—
	Description	December 31,		Quoted Prices in		Significant Other		Unobservable Inputs
		2013		Active Markets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	Assets:
	Cash equivalents	$	9,500	$	—	$	9,500	$	—
	Restricted cash		50		—		50		—
	Short-term investments		3,000		—		3,000		—
	Total	$	12,550	$	—	$	12,550	$	—

Accrued_Expenses_and_Other_Cur

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Accrued Expenses and Other Current Liabilities	5. Accrued Expenses and Other Current Liabilities
	Accrued expenses and other current liabilities consist of the following, in thousands:
		December 31,
		2014		2013
	Employee compensation and benefits	$	528	$	627
	Clinical development expenses		186		665
	Professional fees		165		190
	Research and development costs		118		130
	Other		5		183
	Total accrued expenses and other current liabilities	$	1,002	$	1,795

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies
	License Commitments
	The Company acquires assets under development and enters into research and development arrangements with third parties that often require milestone and royalty payments based on the progress of the asset through development stages. Milestone payments may be required, for example, upon approval of the product for marketing by a regulatory agency. In certain agreements, the Company is required to make royalty payments based upon a percentage of the sales of the products licensed pursuant to such agreements. Because of the contingent nature of these payments, they are not included in the table of contractual obligations shown below (see also Note 11).
	These arrangements may be material individually, and in the unlikely event that milestones for multiple products covered by these arrangements were reached in the same period, the aggregate charge to expense could be material to the results of operations. In addition, these arrangements often give the Company the discretion to unilaterally terminate development of the product, which would allow the Company to avoid making the contingent payments; however, the Company is unlikely to cease development if the compound successfully achieves clinical testing objectives.
	License agreements generally relate to the Company’s obligations associated with our core technologies, RNAi and immunomodulators. The Company continually assesses the progress of its licensed technology and the progress of its research and development efforts as it relates to its licensed technology and may terminate with notice to the licensor at any time. In the event these licenses are terminated, no amounts will be due.
	The Company’s contractual license obligations that will require future cash payments as of December 31, 2014 are as follows, in thousands:
	Year Ending December 31,
	2015	$	478
	2016		150
	2017		150
	2018		150
	2019		150
	Thereafter		530
	Total	$	1,608
	Operating Leases
	The Company leases office and laboratory space for its corporate headquarters in Marlborough, Massachusetts. The lease for the space commenced on April 1, 2014 and will expire in March 2019. The monthly base rent for the premises during the first year was approximately $9,000. Each year thereafter, the base rent shall increase by approximately 3% over the base rent from the prior year. The base rent includes the Company’s pro rata share of the estimated annual real estate taxes and operating expenses.
	Total rent expense under the Company’s operating leases was $107,500 and $62,900 for the years ended December 31, 2014 and 2013, respectively.
	At December 31, 2014, the Company’s future minimum payments required under operating leases are as follows, in thousands:
	Year Ending December 31,
	2015	$	119
	2016		119
	2017		117
	2018		120
	2019		30
	Thereafter		—
	Total	$	505
	The Company applies the disclosure provisions of FASB ASC Topic 460, “Guarantor’s Accounting and Disclosure Requirements for Guarantees, Including Indirect Guarantees of Indebtedness of Others” (“ASC 460”), to its agreements that contain guarantee or indemnification clauses. The Company provides: (i) indemnifications of varying scope and size to certain investors and other parties for certain losses suffered or incurred by the indemnified party in connection with various types of third-party claims; and (ii) indemnifications of varying scope and size to officers and directors against third party claims arising from the services they provide to us. These indemnifications give rise only to the disclosure provisions of ASC 460. To date, the Company has not incurred costs as a result of these obligations and does not expect to incur material costs in the future. Accordingly, the Company has not accrued any liabilities in its financial statements related to these indemnifications.

Convertible_Preferred_Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Convertible Preferred Stock	7. Convertible Preferred Stock
	The Company has authorized up to 10,000,000 shares of preferred stock, $0.0001 par value per share, for issuance. The Company’s Board of Directors is authorized under the Company’s Amended and Restated Articles of Incorporation, to designate the authorized preferred stock into one or more series and to fix and determine such rights, preferences, privileges and restrictions of any series of preferred stock, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, as shall be determined by the Company’s Board of Directors upon its issuance. See also Note 8 to our financial statements for the rights and preferences of the Series A-1 convertible preferred stock (“Series A-1 Preferred Stock”).
	Series A Preferred Stock
	The Company currently has authorized a total of 15,000 shares of Series A convertible preferred stock (“Series A Preferred Stock”), $0.0001 par value per share, for issuance.
	Accounting Treatment
	The Series A Preferred Stock has been classified outside of permanent equity (within the mezzanine section between liabilities and equity on the balance sheets) as the Company may not be able to control the actions necessary to issue the maximum number of common shares needed to provide for a conversion in full of the then outstanding Series A Preferred Stock, at which time a holder of the Series A Preferred Stock may elect to redeem their preferred shares outstanding in the amount equal to the face value per share, plus unpaid accrued dividends. The Company’s Series A-1 Preferred Stock has the same rights, privileges and preferences as the Series A Preferred Stock, but does not provide for any potential payment in cash in the event that the Company has insufficient shares of common stock authorized to honor conversions. Accordingly, the Series A-1 Preferred Stock is classified within permanent equity. The Series A-1 Preferred Stock is discussed further in Note 8.
	Dividends
	Holders of Series A Preferred Stock are entitled to receive cumulative mandatory dividends at the rate per share of seven percent (7%) of the face amount ($1,000 per share) per annum, payable quarterly on each March 31, June 30, September 30 and December 31. Dividends shall be payable in additional shares of Series A Preferred Stock valued for this purpose at the face amount. In the event there are not sufficient authorized Series A Preferred Shares available to pay such a dividend, the dividend shall instead accrete to and increase the face value of the outstanding Series A Preferred Stock. The fair value of the Series A Preferred Stock dividend, which is included in the Company’s net loss applicable to common stockholders, is calculated by multiplying the number of common shares that a preferred holder would receive upon conversion by the closing price of the Company’s common stock on the dividend payment date.
	The Company recorded Series A Preferred Stock dividends of $2,399,000 and $8,198,000 during the years ended December 31, 2014 and 2013, respectively.
	Conversion
	Each holder of shares of Series A Preferred Stock may, at any time and from time to time, convert each of its shares into a number of fully paid and non-assessable shares of common stock at the defined conversion rate. Each share of Series A Preferred Stock is convertible into 2,437.57 shares of common stock. In no event shall any holder of shares of Series A Preferred Stock have the right to convert shares of Series A Preferred Stock into shares of common stock to the extent that, after giving effect to such conversion, the holder, together with any of its affiliates, would beneficially own more than 9.999% of the then-issued and outstanding shares of common stock.
	Exchange Transaction
	On January 24, 2014, the Company entered into an exchange agreement (the “Exchange Agreement”) with Tang Capital Partners, L.P. (“TCP”) pursuant to which TCP exchanged a total of 3,000 shares of Series A Preferred Stock for a like number of shares of Series A-1 Preferred Stock.
	On August 13, 2013, the Company entered into an exchange agreement (the “Prior Exchange Agreement”) with TCP pursuant to which TCP agreed to exchange a total of 2,000 shares of Series A Preferred Stock for a like number of shares of Series A-1 Preferred Stock.
	In both transactions, the terms of the Series A-1 Preferred Stock were identical in all respects to the Series A Preferred Stock, other than the elimination of cash penalties that would potentially be due and payable upon the failure of the Company to have enough shares of common stock available to permit the conversion of Series A-1 Preferred Stock into common stock. The exchange transaction was recognized as a decrease in the face value of the Series A Preferred Stock and a corresponding increase in the face value of the Series A-1 Preferred Stock.
	Liquidation Preference
	The “Liquidation Preference” with respect to a share of Series A Preferred Stock means an amount equal to the face amount of the shares ($1,000 per share) plus all accrued and unpaid dividends on the Series A Preferred Stock (as adjusted for any stock dividends, combinations, splits, recapitalizations and the like with respect to such shares). In the event of a liquidation, dissolution, or winding up, whether voluntary or involuntary, no distribution shall be made to the holders of any shares of capital stock of the Company (other than Senior Securities (as defined in the Certificate of Designations), pursuant to the rights, preferences and privileges thereof) unless prior thereto the holders of shares of Series A Preferred Stock have received the Liquidation Preference with respect to each share then outstanding.
	Voting
	The holders of Series A Preferred Stock do not have any right to elect directors and have only limited voting rights, which consist primarily of the right to vote under certain protective provisions set forth in the Certificate of Designations, regarding: (i) any proposed amendment to the Series A Preferred Stock or its right and preferences; and (ii) any proposed “Deemed Liquidation Event” as defined in the Certificate of Designations.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity
	Series A-1 Preferred Stock
	The Company currently has authorized a total of 10,000 shares of Series A-1 Preferred Stock, $0.0001 par value per share, for issuance. On January 24, 2014, the Company filed a Certificate of Increase with the Secretary of State of the State of Delaware amending the Company’s previously filed Certificate of Designation for the Series A-1 Preferred Stock to increase the total number of shares of Series A-1 Preferred Stock authorized from 5,000 shares to 10,000 shares.
	Accounting Treatment
	The Series A-1 Preferred Stock has been classified as permanent equity as the Company is not required to effect a net cash settlement in the instance that the Company does not have enough shares of common stock available to permit the conversion of Series A-1 Preferred Stock into common stock.
	Dividends
	Holders of Series A-1 Preferred Stock are entitled to receive cumulative mandatory dividends at the rate per share of seven percent (7%) of the face amount ($1,000 per share) per annum, payable quarterly on each March 31, June 30, September 30 and December 31. Dividends shall be payable in additional shares of Series A-1 Preferred Stock valued for this purpose at the face amount. In the event there are not sufficient authorized Series A-1 Preferred Shares available to pay such a dividend, the dividend shall instead accrete to and increase the face value of the outstanding Series A-1 Preferred Stock. The fair value of the Series A-1 Preferred Stock dividend, which is included in the Company’s net loss applicable to common stockholders, is calculated by multiplying the number of common shares that a preferred holder would receive upon conversion by the closing price of the Company’s common stock on the dividend payment date.
	The Company recorded Series A-1 Preferred Stock dividends of $1,731,000 and $412,000 during the years ended December 31, 2014 and 2013, respectively.
	Conversion
	Each holder of shares of Series A-1 Preferred Stock may, at any time and from time to time, convert each of its shares into a number of fully paid and non-assessable shares of common stock at the defined conversion rate. Each share of Series A-1 Preferred Stock is convertible into 2,437.57 shares of common stock. In no event shall any holder of shares of Series A-1 Preferred Stock have the right to convert shares of Series A-1 Preferred Stock into shares of common stock to the extent that such issuance or sale or right to effect such conversion would result in the holder or any of its affiliates together beneficially owning more than 9.999% of the then issued and outstanding shares of common stock.
	Exchange Transaction
	On January 24, 2014, the Company entered into the Exchange Agreement with TCP pursuant to which TCP exchanged a total of 3,000 shares of Series A Preferred Stock for a like number of shares of Series A-1 Preferred Stock.
	On August 13, 2013, the Company entered into the Prior Exchange Agreement with TCP pursuant to which TCP agreed to exchange a total of 2,000 shares of Series A Preferred Stock for a like number of shares of Series A-1 Preferred Stock.
	In both transactions, the terms of the Series A-1 Preferred Stock were identical in all respects to the Series A Preferred Stock, other than the elimination of cash penalties that would potentially be due and payable upon the failure of the Company to have enough shares of common stock available to permit the conversion of Series A-1 Preferred Stock into common stock. The exchange transaction was recognized as a decrease in the face value of the Series A Preferred Stock and a corresponding increase in the face value of the Series A-1 Preferred Stock.
	Liquidation Preference
	The “Liquidation Preference” with respect to a share of Series A-1 Preferred Stock means an amount equal to the face amount of the shares ($1,000 per share) plus all accrued and unpaid dividends on the Series A-1 Preferred Stock (as adjusted for any stock dividends, combinations, splits, recapitalizations and the like with respect to such shares). In the event of a liquidation, dissolution, or winding up, whether voluntary or involuntary, no distribution shall be made to the holders of any shares of capital stock of the Company (other than Senior Securities (as defined in the Certificate of Designations), pursuant to the rights, preferences and privileges thereof) unless prior thereto the holders of shares of Series A-1 Preferred Stock have received the Liquidation Preference with respect to each share then outstanding. The liquidation preference of the Series A Preferred Stock is pari passu with the liquidation preference of the Series A-1 Preferred Stock.
	Voting
	The holders of Series A-1 Preferred Stock do not have any right to elect directors and have only limited voting rights, which consist primarily of the right to vote under certain protective provisions set forth in the Certificate of Designations, regarding: (i) any proposed amendment to the Series A-1 Preferred Stock or its right and preferences; and (ii) any proposed “Deemed Liquidation Event” as defined in the Certificate of Designations.
	Common Stock
	On July 10, 2014, the Company filed a Certificate of Amendment with the Secretary of State of the State of Delaware amending the Company’s previously filed Amended and Restated Certificate of Incorporation to decrease the total number of shares of common stock authorized to 100,000,000. The decrease in the total number of shares of common stock authorized was approved by the Company’s stockholders at the Company’s Annual Meeting of Stockholders held on June 2, 2014.
	On April 22, 2014, the Company entered into a purchase agreement (the “Prior Purchase Agreement”) with Lincoln Park Capital Fund, LLC (“LPC”), pursuant to which and subject to the terms and conditions contained in the Prior Purchase Agreement, the Company had the right to sell to LPC up to $20 million in shares of the Company’s common stock over a 30-month term. The Prior Purchase Agreement was terminable, among other circumstances, by mutual agreement of LPC and the Company at any time. The Company and LPC executed a termination agreement dated December 18, 2014, whereby the parties mutually agreed to terminate the Prior Purchase Agreement effective immediately. The Company sold a total of $2.0 million in shares of common stock to LPC at a price of $4.00 per share and previously issued 100,000 shares of common stock at a price of $4.00 per share as a commitment fee, recorded as a cost of capital, under the Prior Purchase Agreement. As a result of this purchase, the Company received net proceeds of approximately $1.9 million, after deducting commissions and other offering expenses of approximately $0.1 million.
	On December 18, 2014, the Company entered into a purchase agreement (the “Purchase Agreement”) with LPC, pursuant to which the Company has the right to sell to LPC up to $10.8 million in shares of the Company’s common stock, subject to certain limitations and conditions set forth in the Purchase Agreement. Pursuant to the Purchase Agreement, the Company issued 100,000 shares of common stock at price per share of $1.93 as a commitment fee under the Purchase Agreement, which was recorded as a cost of capital. The Company intends to use the net proceeds from this offering for working capital, to fund the development of the Company’s development programs, as well as for other general corporate purposes.
	On March 1, 2013, the Company entered into an asset purchase agreement with OPKO Health, Inc. (“OPKO”) pursuant to which the Company acquired substantially all of OPKO’s RNAi-related assets, including patents, licenses, clinical and preclinical data and other related assets (the “OPKO Asset Purchase”). Upon the close of the OPKO Asset Purchase on March 12, 2013, the Company issued to OPKO 1,666,666 shares of common stock. The asset purchase agreement with OPKO is described further in Note 11.
	On March 6, 2013, the Company entered into a securities purchase agreement with certain purchasers, pursuant to which the Company agreed to issue a total of 3,765,230 shares of common stock at a price of $4.35 per share. The Company received net proceeds of $15.7 million from the Offering, which closed on March 12, 2013, after deducting payment of commissions and other costs of $0.7 million.
	During the years ended December 31, 2014 and 2013, the Company issued 9,463,712 and 1,056,684 shares of common stock as a result of Series A and Series A-1 Preferred Stock conversions.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation
	Stock Plans
	On January 23, 2012, the Company’s Board of Directors and sole stockholder adopted the RXi Pharmaceuticals Corporation 2012 Long-Term Incentive Plan (the “2012 Incentive Plan”). Under the 2012 Incentive Plan, the Company may grant incentive stock options, nonqualified stock options, cash awards, stock appreciation rights, restricted and unrestricted stock and stock unit awards and other stock-based awards. The Company’s Board of Directors currently acts as the administrator of the Company’s 2012 Incentive Plan. The administrator has the power to select participants from among the key employees, directors and consultants of and advisors to the Company, establish the terms, conditions and vesting schedule, if applicable, of each award and to accelerate vesting or exercisability of any award.
	As of December 31, 2014, an aggregate of 5,000,000 shares of common stock were reserved for issuance under the Company’s 2012 Incentive Plan, including 3,000,264 shares subject to outstanding common stock options granted under the 2012 Incentive Plan and 1,997,736 shares available for future grants. Each option shall expire within ten years of issuance. Stock options granted by the Company to employees generally vest as to 12.5% of the shares on the six-month and first anniversary of the grant date and 25% of the shares at the end of each successive three-year period until fully vested.
	Stock-Based Compensation
	The Company follows the provisions of ASC 718, which requires the measurement and recognition of compensation expense for all stock-based payment awards made to employees and non-employee directors including employee stock options. Stock compensation expense based on the grant date fair value estimated in accordance with the provisions of ASC 718 is recognized as an expense over the requisite service period.
	For stock options granted as consideration for services rendered by non-employees, the Company recognizes compensation expense in accordance with the requirements of FASB ASC Topic 505-50, “Equity Based Payments to Non-Employees.” Non-employee option grants that do not vest immediately upon grant are recorded as an expense over the requisite service period of the underlying stock options. At the end of each financial reporting period prior to vesting, the value of these options, as calculated using the Black-Scholes option-pricing model, will be re-measured using the fair value of the Company’s common stock and the non-cash compensation recognized during the period will be adjusted accordingly. Since the fair value of options granted to non-employees is subject to change in the future, the amount of the future compensation expense will include fair value re-measurements until the stock options are fully vested.
	The Company is currently using the Black-Scholes option-pricing model to determine the fair value of all its option grants. For option grants for the years ended December 31, 2014 and 2013, the following assumptions were used:
		Year ended December 31,
		2014		2013
	Risk-free interest rate	1.60% - 2.73%		0.71% - 2.19%
	Expected volatility	97.91% - 107.01%		74.53% - 107.30%
	Weighted average expected volatility	101.52%		76.27%
	Expected life (in years)	5.20 - 10.00		5.20 - 10.00
	Expected dividend yield	0.00%		0.00%
	The weighted-average fair value of options granted during the years ended December 31, 2014 and 2013 was $2.43 and $4.05 per share, respectively.
	The risk-free interest rate used for each grant was based upon the yield on zero-coupon U.S. Treasury securities with a term similar to the expected life of the related option. The Company’s expected stock price volatility assumption is based upon the volatility of a composition of comparable companies. The expected life assumption for employee grants was based upon the simplified method provided for under ASC 718 and the expected life assumption for non-employees was based upon the contractual term of the option. The dividend yield assumption of zero is based upon the fact that the Company has never paid cash dividends and presently has no intention of paying cash dividends.
	The following table summarizes the option activity of the Company:
		Total Number				Weighted-		Weighted-		Aggregate
		of Shares				Average		Average		Intrinsic
						Exercise		Remaining		Value
						Price		Contractual
						Per Share		Term
	Balance at December 31, 2013		2,556,269			$	3.47
	Granted		443,995				2.96
	Exercised		—				—
	Cancelled		—				—
	Balance at December 31, 2014		3,000,264			$	3.39		7.86 years	$	—
	Exercisable at December 31, 2014		1,739,455			$	3.39		7.60 years	$	—
	Stock-based compensation expense for the years ended December 31, 2014 and 2013 was approximately $1,846,000 and $1,979,000, respectively. Of this, the Company recognized approximately $81,000 and $43,000 of expense related to non-employee stock options for the same period. There is no income tax benefit as the Company is currently operating at a loss and an actual income tax benefit may not be realized.
	The intrinsic value of stock options exercised was $2,000 for the year ended December 31, 2013. No options were exercised during the year ended December 31, 2014.
	As of December 31, 2014, the compensation expense for all unvested stock options in the amount of approximately $2,700,000 will be recognized in the Company’s results of operations over a weighted average period of 2.02 years.
	Employee Stock Purchase Plan
	On June 7, 2013, the Compensation Committee approved an employee stock purchase plan (“ESPP”), which was subsequently approved by the Company’s stockholders at the Company’s 2014 Annual Meeting of Stockholders. The ESPP allows employees to contribute a percentage of their cash earnings, subject to certain maximum amounts, to be used to purchase shares of the Company’s common stock on each of two semi-annual purchase dates. The purchase price is equal to 90% of the market value per share on either (a) the date of grant of a purchase right under the ESPP or (b) the date on which such purchase right is deemed exercised, whichever is lower.
	As of December 31, 2014, an aggregate of 113,333 shares of common stock were reserved for issuance under the Company’s ESPP, of which 43,780 shares of common stock have been issued under the ESPP and 69,553 shares are available for future issuances.
	The Company is currently using the Black-Scholes option-pricing model to determine the fair value of the ESPP stock rights. For stock rights issued in the years ended December 31, 2014 and 2013, the following assumptions were used:
		Year Ended December 31,
		2014		2013
	Risk-free interest rate	0.06% - 0.09%			0.09	%
	Expected volatility	94.99% - 103.36%			88.68	%
	Weighted average expected volatility	100.39%			88.68	%
	Expected life (in years)	0.5			0.5
	Expected dividend yield	0			0	%
	The weighted average fair value of stock purchase rights granted as part of the ESPP was $1.20 and $2.04 for the years ended December 31, 2014 and 2013.
	The risk-free interest rate used was based upon the yield on zero-coupon U.S. Treasury securities with a term similar to the expected life of the related option. The Company’s expected volatility is based upon the volatility of a composition of comparable companies for the expected term. The expected life assumption was based upon the purchase period and the dividend yield assumption of zero is based upon the fact that the Company has never paid cash dividends and presently has no intention of paying cash dividends.
	The Company recorded $28,800 and $10,200 of stock-based compensation expense for the year ended December 31, 2014 and 2013, respectively, related to the ESPP.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes
	The components of federal and state income tax expense are as follows (in thousands):
		Year Ended
		December 31,
		2014			2013
	Current
	Federal	$	—		$	—
	State		—			—
	Total current		—			—
	Deferred
	Federal		(2,727	)		(9,123	)
	State		(583	)		(2,002	)
	Total deferred		(3,310	)		(11,125	)
	Valuation allowance		3,310			11,125
	Total income tax expense	$	—		$	—
	The components of net deferred tax assets are as follows (in thousands):
		As of December 31,
		2014			2013
	Net operating loss carryforwards	$	9,805		$	6,590
	Tax credit carryforwards		261			146
	Stock based compensation		1,392			861
	Licensing deduction deferral		6,367			6,864
	Other timing differences		110			165
	Gross deferred tax assets		17,935			14,626
	Valuation allowance		(17,935	)		(14,626	)
	Net deferred tax asset	$	—		$	—
	The Company’s deferred tax assets at December 31, 2014 and 2013 consisted primarily of its net operating loss carryforwards, deferred compensation, tax credit carryforwards, Section 197 intangible assets capitalized for federal income tax purposes and certain accruals that for tax purposes are not deductible until future payment is made.
	The Company has incurred net operating losses since inception. At December 31, 2014, the Company had federal and state net operating loss carryforwards of approximately $46.8 million, which are available to reduce future taxable income expiring through 2034. Based on an assessment of all available evidence including, but not limited to the Company’s limited operating history in its core business and lack of profitability, uncertainties of the commercial viability of its technology, the impact of government regulation and healthcare reform initiatives, and other risks normally associated with biotechnology companies, the Company has concluded that it is more likely than not that these net operating loss carryforwards and credits will not be realized and, as a result, a full deferred income tax valuation allowance has been recorded against these assets.
	Under the provisions of the Internal Revenue Code, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss carryforwards and research and development credit carryforwards which could be utilized annually to offset future taxable income and taxes payable.
	The Company files income tax returns in the United States, Massachusetts and New Jersey. The Company is subject to tax examinations for Federal and state purposes for tax years 2012 through 2014. The Company has not recorded any uncertain tax positions as of December 31, 2014 or 2013. The Company does not believe there will be any material changes in its unrecognized tax positions over the next 12 months. RXi has not incurred any interest or penalties. In the event that the Company is assessed interest or penalties at some point in the future, they will be classified in the financial statements as general and administrative expenses.

License_Agreements

License Agreements	12 Months Ended
	Dec. 31, 2014
Research and Development [Abstract]
License Agreements	11. License Agreements
	As part of its business, the Company enters into licensing agreements with third parties that often require milestone and royalty payments based on the progress of the asset through development stages. Milestone payments may be required, for example, upon approval of the product for marketing by a regulatory agency. In certain agreements, the Company is required to make royalty payments based upon a percentage of the sales of the products licensed pursuant to such agreements.
	The expenditures required under these arrangements may be material individually in the event that the Company develops product candidates covered by the intellectual property licensed under any such arrangement, and in the unlikely event that milestones for multiple products covered by these arrangements were reached in the same period, the aggregate charge to expense could be material to the results of operations. In addition, these arrangements often give the Company discretion to unilaterally terminate development of the product, which would allow the Company to avoid making the contingent payments; however, the Company is unlikely to cease development if the compound successfully achieves clinical testing objectives.
	Advirna. We have entered into agreements with Advirna, or their surviving entity, pursuant to which Advirna assigned to us its existing patent and technology rights related to sd-rxRNA technology in exchange for our agreement to pay Advirna an annual maintenance fee of $100,000. Pursuant to the terms of the agreement, in the first quarter of 2014 we paid to Advirna and recorded research and development expense of $350,000 for a one-time milestone payment upon the issuance of the first patent with valid claims covering the assigned technology. Additionally, we will be required to pay a 1% royalty to Advirna on any licensing revenue received by us with respect to future licensing of the assigned Advirna patent and technology rights. We also granted back to Advirna a license under the assigned patent and technology rights for fields of use outside human therapeutics.
	Our rights under the Advirna agreement will expire upon the later of: (i) the expiration of the last-to-expire of the “patent rights” (as defined) included in the Advirna agreement; or (ii) the abandonment of the last-to-be abandoned of such patents, unless earlier terminated in accordance with the provisions of the agreement.
	We may terminate the Advirna agreement at any time upon 90 days’ written notice to Advirna, and Advirna may terminate the agreement upon 90 days’ prior written notice in the event that we cease using commercially reasonable efforts to research, develop, license or otherwise commercialize the patent rights or “royalty-bearing products” (as defined), provided that we may refute such claim within such 90-day period by showing budgeted expenditures for the research, development, licensing or other commercialization consistent with other technologies of similar stage of development and commercial potential as the patent rights or royalty-bearing products. Further, either party at any time may provide to the other party written notice of a material breach of the agreement. If the other party fails to cure the identified breach within 90 days after the date of the notice, the aggrieved party may terminate the agreement by written notice to the party in breach.
	OPKO. In March 2013, we acquired from OPKO substantially all of its RNAi-related assets, which included patents and patent applications, licenses, clinical and preclinical data and other related assets. In exchange for the assets that we purchased from OPKO, we issued to OPKO 1,666,666 shares of our common stock and agreed to pay, if applicable: (i) up to $50 million in development and commercialization milestones for the successful development and commercialization of each “Qualified Drug” (as defined in the Asset Purchase Agreement with OPKO); and (ii) royalty payments equal to: (a) a mid-single-digit percentage of “Net Sales” (as defined in the Asset Purchase Agreement) with respect to each Qualified Drug sold for an ophthalmologic use during the applicable “Royalty Period” (as defined in the Asset Purchase Agreement); and (b) a low-single-digit percentage of Net Sales with respect to each Qualified Drug sold for a non-ophthalmologic use during the applicable Royalty Period (collectively, the “Royalty Payments”). The Company recorded research and development expense of $12,250,000 during the year ended December 31, 2013 to recognize the fair value of the common shares issued to OPKO in exchange for the RNAi-related assets acquired by the Company.
	Hapten. On December 17, 2014, the Company entered into an assignment and exclusive license agreement, (the “Assignment and License Agreement”) with Hapten Pharmaceuticals, LLC (“Hapten”) under which Hapten agreed, effective at a closing that was subject to the satisfaction of certain closing conditions which occurred in February 2015, to sell and assign to us certain patent rights and related assets and rights, including an investigational new drug application and clinical data, for Hapten’s Samcyprone™ gel products for therapeutic and prophylactic use. Samcyprone™ is a proprietary gel formulation of diphenylcyclopropenone (“DPCP”), an immunomodulation agent that works by initiating a T-cell response. Hapten has been developing Samcyprone™ for the treatment of alopecia areata, warts and cutaneous metastases of malignant melanoma.
	Under the Assignment and License Agreement, Hapten will receive at closing an upfront payment from us, payable in cash and stock, and will be entitled to receive: (i) future milestone payments tied to the achievement of certain clinical and commercial objectives (all of which payments may be made at our option in cash or through the issuance of common stock); and (ii) escalating royalties based on product sales by us and any sublicensees. The Assignment and License Agreement with Hapten is described further in Note 12.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	12. Subsequent Events
	Subsequent to the balance sheet date and up to March 30, 2015, a total of 50,000 shares of common stock were sold to LPC pursuant to the Purchase Agreement, with proceeds received from such transactions totaling $65,000.
	Subsequent to the balance sheet date and up to March 30, 2015, the Company issued 8,987,326 shares of common stock as a result of Series A and A-1 Preferred Stock conversions.
	On February 4, 2015, the Company closed the Assignment and License Agreement with Hapten. Pursuant to the Assignment and License Agreement, the Company paid $100,000 in cash to Hapten as consideration for a license fee and issued 200,000 shares of common stock at a share price of $1.14 as additional consideration.
	On March 20, 2015, the Company entered into an exchange agreement with TCP pursuant to which TCP exchanged a total of 2,000 shares of Series A Preferred Stock for a like number of shares of Series A-1 Preferred Stock. The terms of the Series A-1 Preferred Stock are identical in all respects to the Series A Preferred Stock, other than the elimination of cash penalties that would potentially be due and payable upon the failure of the Company to have enough shares of common stock available to permit the conversion of Series A Preferred Stock into common stock. This exchange transaction will be recognized as a decrease in the face value of the Series A Preferred Stock and a corresponding increase in the face value of the Series A-1 Preferred Stock.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation — The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”).
Uses of Estimates in Preparation of Financial Statements	Uses of Estimates in Preparation of Financial Statements — The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from these estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents — The Company considers all highly liquid debt instruments with an original maturity of three months or less to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts and certificates of deposit.
Restricted Cash	Restricted Cash — Restricted cash consists of certificates of deposit held by financial institutions as collateral for the Company’s corporate credit cards.
Short-term Investments	Short-term Investments — The Company’s short-term investments consist of certificates of deposit with original maturities ranging from three months to one year.
Concentrations of Credit Risk	Concentrations of Credit Risk — Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents and short-term investments. The Company maintains cash balances in several accounts with one bank, which at times are in excess of federally insured limits. The Company has established guidelines related to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company’s investments are maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the exposure of any single issuer.
Fair Value of Financial Instruments	Fair Value of Financial Instruments — The carrying amounts reported in the balance sheet for cash equivalents, restricted cash, short-term investments and accounts payable approximate their fair values due to their short-term nature or market rates of interest.
Equipment and Furnishings	Equipment and Furnishings — Equipment and furnishings are stated at cost and depreciated using the straight-line method based on the estimated useful lives of the related assets. The Company provides for depreciation over the assets’ estimated useful lives as follows:
	Computer equipment		3 years
	Machinery & equipment		5 years
	Office furniture		5 years
	Depreciation and amortization expense for the years ended December 31, 2014 and 2013 was approximately $87,000 and $99,000, respectively.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets — The Company reviews long-lived assets for impairment on an annual basis, as of December 31, or on an interim basis if an event occurs that might reduce the fair value of such assets below their carrying values. An impairment loss would be recognized based on the difference between the carrying value of the asset and its estimated fair value, which would be determined based on either discounted future cash flows or other appropriate fair value methods. The Company believes no impairment existed as of December 31, 2014 and 2013.
Revenue Recognition	Revenue Recognition — The Company recognizes revenue when all of the following criteria are met: there is persuasive evidence of an arrangement, the fee is fixed or determinable, delivery has occurred or services have been rendered and collection of the related receivable is reasonably assured. The Company may generate revenue from product sales, license agreements, collaborative research and development arrangements, and government grants. To date the Company’s principal source of revenue consists of government research grants. Revenue from a government grant is recognized over the respective contract periods as the services are performed. Monies received prior to the recognition of revenue are recorded as deferred revenue.
Stock-based Compensation	Stock-based Compensation — The Company follows the provisions of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 718, “Compensation – Stock Compensation” (“ASC 718”) which requires the measurement and recognition of compensation expense for all stock-based payment awards made to employees, officers and non-employee directors, including stock options. Stock compensation expense based on the grant date fair value estimated in accordance with the provisions of ASC 718 is recognized as an expense over the requisite service period.
	For stock options granted as consideration for services rendered by non-employees, the Company recognizes compensation expense in accordance with the requirements of FASB ASC Topic 505-50, “Equity Based Payments to Non-Employees.” Non-employee option grants that do not vest immediately upon grant are recorded as an expense over the requisite service period of the underlying stock options. At the end of each financial reporting period prior to vesting, the value of these options, as calculated using the Black-Scholes option-pricing model, will be re-measured using the fair value of the Company’s common stock and the non-cash compensation recognized during the period will be adjusted accordingly. Since the fair market value of options granted to non-employees is subject to change in the future, the amount of the future compensation expense will include fair value re-measurements until the stock options are fully vested.
Research and Development Expenses	Research and Development Expenses — Research and development costs are charged to expense as incurred and relate to salaries, employee benefits, facility-related expenses, supplies, share-based compensation related to employees and non-employees involved in the Company’s research and development, external services, other operating costs and overhead related to our research and development departments, costs to acquire technology licenses and expenses associated with preclinical activities and our clinical trials. Payments made by the Company in advance for research and development services not yet provided and/or for materials not yet received are recorded as prepaid expenses. Accrued liabilities are recorded related to those expenses for which vendors have not yet billed us with respect to services provided and/or materials that we have received.
	Preclinical and clinical trial expenses relate to third-party services, subject-related fees at the sites where our clinical trials are being conducted, laboratory costs, analysis costs, toxicology studies and investigator fees. Costs associated with these expenses are generally payable on the passage of time or when certain milestones are achieved. Expense is recorded during the period incurred or in the period in which a milestone is achieved. In order to ensure that we have adequately provided for preclinical and clinical expenses during the proper period, we maintain an accrual to cover these expenses. These accruals are assessed on a quarterly basis and are based on such assumptions as expected total cost, the number of subjects and clinical trial sites and length of the study. Actual results may differ from these estimates and could have a material impact on our reported results. Our historical accrual estimates have not been materially different from our actual costs.
Patents and Patent Application Costs	Patents and Patent Application Costs — Although the Company believes that its patents and underlying technology have continuing value, the amount of future benefits to be derived from the patents is uncertain. Patent costs are, therefore, expensed as incurred.
Income Taxes	Income Taxes — The Company recognizes assets or liabilities for the deferred tax consequences of temporary differences between the tax basis of assets or liabilities and their reported amounts in the financial statements in accordance with FASB ASC 740, “Accounting for Income Taxes” (“ASC 740”). These temporary differences will result in taxable or deductible amounts in future years when the reported amounts of the assets or liabilities are recovered or settled. ASC 740 requires that a valuation allowance be established when management determines that it is more likely than not that all or a portion of a deferred asset will not be realized. The Company evaluates the realizability of its net deferred income tax assets and valuation allowances as necessary, at least on an annual basis. During this evaluation, the Company reviews its forecasts of income in conjunction with other positive and negative evidence surrounding the realizability of its deferred income tax assets to determine if a valuation allowance is required. Adjustments to the valuation allowance will increase or decrease the Company’s income tax provision or benefit. The recognition and measurement of benefits related to the Company’s tax positions requires significant judgment, as uncertainties often exist with respect to new laws, new interpretations of existing laws, and rulings by taxing authorities. Differences between actual results and the Company’s assumptions or changes in the Company’s assumptions in future periods are recorded in the period they become known.
Comprehensive Loss	Comprehensive Loss — The Company’s comprehensive loss is equal to its net loss for all periods presented.
Net Loss per Share	Net Loss per Share — The Company accounts for and discloses net loss per common share in accordance with FASB ASC Topic 260, “Earnings per Share.” Basic and diluted net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted average number of common shares outstanding. When the effects are not anti-dilutive, diluted earnings per share is computed by dividing the Company’s net earnings by the weighted average number of common shares outstanding and the impact of all dilutive potential common shares.
	The following table sets forth the potential common shares excluded from the calculation of net loss per common share because their inclusion would be anti-dilutive:
		December 31,
		2014		2013
	Options to purchase common stock		3,000,264		2,556,269
	Common stock underlying Series A and Series A-1 convertible preferred stock		16,300,969		24,313,108
	Warrants to purchase common stock		4,615		4,615
	Total		19,305,848		26,873,992

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Depreciation Over Assets' Estimated Useful Lives	The Company provides for depreciation over the assets’ estimated useful lives as follows:
	Computer equipment		3 years
	Machinery & equipment		5 years
	Office furniture		5 years
Common Shares Excluded from Calculation of Net Loss Per Common Share	The following table sets forth the potential common shares excluded from the calculation of net loss per common share because their inclusion would be anti-dilutive:
		December 31,
		2014		2013
	Options to purchase common stock		3,000,264		2,556,269
	Common stock underlying Series A and Series A-1 convertible preferred stock		16,300,969		24,313,108
	Warrants to purchase common stock		4,615		4,615
	Total		19,305,848		26,873,992

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	The assets classified as Level 2 have initially been valued at transaction price and subsequently valued, at the end of each reporting period, using other market observable data. Observable market data points include quoted prices, interest rates, reportable trades and other industry and economic events. Financial assets measured at fair value on a recurring basis are summarized as follows, in thousands:
	Description	December 31,		Quoted Prices in		Significant Other		Unobservable Inputs
		2014		Active Markets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	Assets:
	Cash equivalents	$	4,000	$	—	$	4,000	$	—
	Restricted cash		50		—		50		—
	Total	$	4,050	$	—	$	4,050	$	—
	Description	December 31,		Quoted Prices in		Significant Other		Unobservable Inputs
		2013		Active Markets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	Assets:
	Cash equivalents	$	9,500	$	—	$	9,500	$	—
	Restricted cash		50		—		50		—
	Short-term investments		3,000		—		3,000		—
	Total	$	12,550	$	—	$	12,550	$	—

Accrued_Expenses_and_Other_Cur1

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following, in thousands:
		December 31,
		2014		2013
	Employee compensation and benefits	$	528	$	627
	Clinical development expenses		186		665
	Professional fees		165		190
	Research and development costs		118		130
	Other		5		183
	Total accrued expenses and other current liabilities	$	1,002	$	1,795

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Cash Payments	The Company’s contractual license obligations that will require future cash payments as of December 31, 2014 are as follows, in thousands:
	Year Ending December 31,
	2015	$	478
	2016		150
	2017		150
	2018		150
	2019		150
	Thereafter		530
	Total	$	1,608
Company's Future Minimum Payments	At December 31, 2014, the Company’s future minimum payments required under operating leases are as follows, in thousands:
	Year Ending December 31,
	2015	$	119
	2016		119
	2017		117
	2018		120
	2019		30
	Thereafter		—
	Total	$	505

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Assumptions Used to Determine Fair Value of Employee Stock Purchase Plan Stock Rights	The Company is currently using the Black-Scholes option-pricing model to determine the fair value of the ESPP stock rights. For stock rights issued in the years ended December 31, 2014 and 2013, the following assumptions were used:
		Year Ended December 31,
		2014		2013
	Risk-free interest rate	0.06% - 0.09%			0.09	%
	Expected volatility	94.99% - 103.36%			88.68	%
	Weighted average expected volatility	100.39%			88.68	%
	Expected life (in years)	0.5			0.5
	Expected dividend yield	0			0	%
Summary of Option Activity	The following table summarizes the option activity of the Company:
		Total Number				Weighted-		Weighted-		Aggregate
		of Shares				Average		Average		Intrinsic
						Exercise		Remaining		Value
						Price		Contractual
						Per Share		Term
	Balance at December 31, 2013		2,556,269			$	3.47
	Granted		443,995				2.96
	Exercised		—				—
	Cancelled		—				—
	Balance at December 31, 2014		3,000,264			$	3.39		7.86 years	$	—
	Exercisable at December 31, 2014		1,739,455			$	3.39		7.60 years	$	—
Schedule of Assumptions Used to Determine Fair Value of Option Grants	The Company is currently using the Black-Scholes option-pricing model to determine the fair value of all its option grants. For option grants for the years ended December 31, 2014 and 2013, the following assumptions were used:
		Year ended December 31,
		2014		2013
	Risk-free interest rate	1.60% - 2.73%		0.71% - 2.19%
	Expected volatility	97.91% - 107.01%		74.53% - 107.30%
	Weighted average expected volatility	101.52%		76.27%
	Expected life (in years)	5.20 - 10.00		5.20 - 10.00
	Expected dividend yield	0.00%		0.00%

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Components of Federal and State Income Tax Expense	The components of federal and state income tax expense are as follows (in thousands):
		Year Ended
		December 31,
		2014			2013
	Current
	Federal	$	—		$	—
	State		—			—
	Total current		—			—
	Deferred
	Federal		(2,727	)		(9,123	)
	State		(583	)		(2,002	)
	Total deferred		(3,310	)		(11,125	)
	Valuation allowance		3,310			11,125
	Total income tax expense	$	—		$	—
Components of Net Deferred Tax Assets	The components of net deferred tax assets are as follows (in thousands):
		As of December 31,
		2014			2013
	Net operating loss carryforwards	$	9,805		$	6,590
	Tax credit carryforwards		261			146
	Stock based compensation		1,392			861
	Licensing deduction deferral		6,367			6,864
	Other timing differences		110			165
	Gross deferred tax assets		17,935			14,626
	Valuation allowance		(17,935	)		(14,626	)
	Net deferred tax asset	$	—		$	—

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Cash equivalent maturity period	Three months or less
Short term investments maturity period	Three months to one year.
Depreciation and amortization	$87,000	$99,000
Impairment of long lived assets	$0	$0

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Schedule of Property Plant and Equipment Useful Life (Detail)	12 Months Ended
	Dec. 31, 2014
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	3 years
Machinery & Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	5 years
Office Furniture [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	5 years

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Common Shares Excluded from Calculation of Net Loss Per Common Share (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	19,305,848	26,873,992
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	3,000,264	2,556,269
Common Stock Underlying Series A and Series A-1 Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	16,300,969	24,313,108
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total amount of anti-dilutive securities excluded from computation of earnings per share	4,615	4,615

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Measurements (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:
Restricted cash	$50	$50
Short-term investments		3,000
Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents	4,000	9,500
Restricted cash	50	50
Short-term investments		3,000
Total	4,050	12,550
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Cash equivalents	4,000	9,500
Restricted cash	50	50
Short-term investments		3,000
Total	$4,050	$12,550

Accrued_Expenses_and_Other_Cur2

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Liabilities and Other Liabilities [Abstract]
Employee compensation and benefits	$528	$627
Clinical development expenses	186	665
Professional fees	165	190
Research and development costs	118	130
Other	5	183
Total accrued expenses and other current liabilities	$1,002	$1,795

Commitments_and_Contingencies_1

Commitments and Contingencies - Schedule of Future Cash Payments (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$478
2016	150
2017	150
2018	150
2019	150
Thereafter	530
Total	$1,608

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Lease agreement commencement date	4/1/14
Lease agreement maturity date	31-Mar-19
Approximate monthly base rent	$9,000
Annual increase in base rent percentage	3.00%
Operating lease expenses	$107,500	$62,900

Commitments_and_Contingencies_3

Commitments and Contingencies - Company's Future Minimum Payments (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$119
2016	119
2017	117
2018	120
2019	30
Thereafter	0
Total	$505

Convertible_Preferred_Stock_Ad

Convertible Preferred Stock - Additional Information (Detail) (USD $)	0 Months Ended		12 Months Ended
	Jan. 24, 2014	Aug. 13, 2013	Dec. 31, 2014	Dec. 31, 2013	Jan. 24, 2014
Class of Stock [Line Items]
Preferred stock, shares authorized			10,000,000	10,000,000
Preferred stock, par value, per share			$0.00	$0.00
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized			15,000	15,000
Preferred stock, par value			$0.00	$0.00
Preferred stock, dividend rate per share			7.00%
Preferred stock, face amount			$1,000
Fair value of Series A Preferred Stock dividends			$2,399,000	$8,198,000
Preferred Stock convertible to common stock			2,437.57
Percentage of affiliates owning shares			10.00%
Shares of Series A Preferred Stock exchanged for Series A-1 Preferred Stock			-3,000	-2,000
Series A-1 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	5,000		10,000	10,000	5,000
Preferred stock, par value, per share			$0.00	$0.00
Preferred stock, dividend rate per share			7.00%
Preferred stock, face amount			$1,000
Preferred Stock convertible to common stock			2,437.57
Percentage of affiliates owning shares			10.00%
Shares of Series A Preferred Stock exchanged for Series A-1 Preferred Stock	3,000	2,000	3,000	2,000
Capital distribution			$0

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended		0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 18, 2014	Apr. 22, 2014	Mar. 06, 2013	Mar. 01, 2013	Jan. 24, 2014	Aug. 13, 2013	Jul. 10, 2014
Class of Stock [Line Items]
Preferred stock, par value, per share	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Fair value of Series A-1 Preferred Stock dividends	$4,130,000	$8,610,000
Common stock, shares authorized	100,000,000	100,000,000							100,000,000
Common stock shares issued price	1,886,000	15,651,000
Commissions and other offering expenses related to stock issuance	114,000	727,000
Proceeds from issues of share	1,886,000	15,651,000
Lincoln Park Capital Fund, LLC [Member]
Class of Stock [Line Items]
Stock reserved during period, value			10,800,000	20,000,000
Common stock shares issued price			2,000,000
Stock issued during period, per share price			$4
Stock issued as a commitment fee, shares			100,000
Common stock issued under securities purchase agreement, per shares			$4
Stock issued during period, net Proceeds			1,900,000
Commissions and other offering expenses related to stock issuance			100,000
Common Stock [Member]
Class of Stock [Line Items]
Common stock shares issued price		1,000
Commissions and other offering expenses related to stock issuance	114,000	727,000
Common stock, issued		1,666,666
Common stock issued under securities purchase agreement	700,000	3,765,230			3,765,230
Proceeds from issues of share					15,700,000
Commissions and other costs					700,000
Number of common stock issued upon conversion of preferred stock	9,463,712	1,056,684
OPKO Health, Inc.[Member]
Class of Stock [Line Items]
Common stock issued under securities purchase agreement, per shares					$4.35
Common stock, issued	1,666,666					1,666,666
Series A-1 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value, per share	$0.00	$0.00
Preferred stock, shares authorized	10,000	10,000					5,000
Preferred stock, dividend rate per share	7.00%
Preferred stock, face amount	$1,000
Fair value of Series A-1 Preferred Stock dividends	1,731,000	412,000
Percentage of affiliates owning shares	10.00%
Preferred Stock convertible to common stock	2,437.57
Shares of Series A Preferred Stock exchanged for Series A-1 Preferred Stock	3,000	2,000					3,000	2,000
Capital distribution	$0
Number of common stock issued upon conversion of preferred stock	-3,716

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended		0 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Jun. 07, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	5,000,000	5,000,000
Purchase of common stock	3,000,264	3,000,264	2,556,269
Shares available for future issuances	1,997,736	1,997,736
Expiration period of Option		10 years
Percentage of vesting of stock option on completion of first and second eligible service period		12.50%
Percentage of vesting of stock option for remaining subsequent eligible service period		25.00%
Description of stock option granted		Stock options granted by the Company to employees generally vest as to 12.5% of the shares on the six-month and first anniversary of the grant date and 25% of the shares at the end of each successive three-year period until fully vested.
Weighted average grant date fair value per share of options granted		$2.43	$4.05
Dividend yield		0.00%	0.00%
Stock-based compensation expense		$1,846,000	$1,979,000
Stock-based compensation expense, non-employee stock options		81,000	43,000
Stock-based compensation expense tax benefit		0
Aggregate intrinsic value of exercisable options		0	2,000
Unrecognized share based compensation expense on unvested stock option	2,700,000	2,700,000
Unrecognized share based compensation expense on unvested stock option period of recognition	2 years 7 days
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	113,333	113,333
Purchase of common stock	43,780	43,780
Shares available for future issuances	69,553	69,553
Weighted average grant date fair value per share of options granted		$1.20	$2.04
Dividend yield		0.00%	0.00%
Percentage of common share offer price as to market price				90.00%
Stock-based compensation expense related to the ESPP		$28,800	$10,200

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Assumptions Used to Determine Fair Value of Option Grants (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum	1.60%	0.71%
Risk-free interest rate, Maximum	2.73%	2.19%
Expected volatility, Minimum	97.91%	74.53%
Expected volatility, Maximum	107.01%	107.30%
Weighted average expected volatility	101.52%	76.27%
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	5 years 2 months 12 days	5 years 2 months 12 days
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	10 years	10 years

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total Number of Shares, Beginning Balance	2,556,269
Total Number of Shares, Granted	443,995
Total Number of Shares, Exercised	0
Total Number of Shares, Cancelled	0
Total Number of Shares, Ending Balance	3,000,264
Total Number of Shares, Exercisable	1,739,455
Weighted-Average Exercise Price Per Share, Beginning Balance	$3.47
Weighted-Average Exercise Price Per Share, Granted	$2.96
Weighted-Average Exercise Price Per Share, Exercised	$0
Weighted-Average Exercise Price Per Share, Cancelled	$0
Weighted-Average Exercise Price Per Share, Ending Balance	$3.39
Weighted-Average Exercise Price Per Share, Exercisable	$3.39
Weighted-Average Remaining Contractual Term, Ending Balance	7 years 10 months 10 days
Weighted-Average Remaining Contractual Term, Exercisable	7 years 7 months 6 days
Aggregate Intrinsic Value, Ending Balance	$0
Aggregate Intrinsic Value, Exercisable	$0

StockBased_Compensation_Schedu1

Stock-Based Compensation - Schedule of Assumptions Used to Determine Fair Value of Employee Stock Purchase Plan Stock Rights (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.60%	0.71%
Risk-free interest rate	2.73%	2.19%
Expected volatility	97.91%	74.53%
Expected volatility	107.01%	107.30%
Weighted average expected volatility	101.52%	76.27%
Expected dividend yield	0.00%	0.00%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.06%	0.09%
Risk-free interest rate	0.09%
Expected volatility	94.99%	88.68%
Expected volatility	103.36%
Weighted average expected volatility	100.39%	88.68%
Expected life (in years)	6 months	6 months
Expected dividend yield	0.00%	0.00%

Income_Taxes_Components_of_Fed

Income Taxes - Components of Federal and State Income Tax Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$0	$0
State	0	0
Total current	0	0
Deferred
Federal	-2,727	-9,123
State	-583	-2,002
Total deferred	-3,310	-11,125
Valuation allowance	3,310	11,125
Total income tax expense	$0	$0

Income_Taxes_Components_of_Net

Income Taxes - Components of Net Deferred Tax Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$9,805	$6,590
Tax credit carryforwards	261	146
Stock based compensation	1,392	861
Licensing deduction deferral	6,367	6,864
Other timing differences	110	165
Gross deferred tax assets	17,935	14,626
Valuation allowance	-17,935	-14,626
Net deferred tax asset	$0	$0

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$46,800,000
Expiration of carry forwards loss	2034
Liability for uncertain tax positions	$0	$0
Earliest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax year subject to tax examination	2012
Latest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax year subject to tax examination	2014

License_Agreements_Additional_

License Agreements - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Mar. 01, 2013	Dec. 31, 2014	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Fair value of common stock issued in exchange for research and development expense			$12,250,000
OPKO Health, Inc.[Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Common stock, issued	1,666,666	1,666,666
Development and commercialization milestones		50,000,000
Fair value of common stock issued in exchange for research and development expense			12,250,000
Advirna [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual maintenance fee		100,000
Royalty payments		1.00%
Effective license period		90 days
Advirna [Member] | Research and Development Expense [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
One-time milestone payment		$350,000

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	12 Months Ended		0 Months Ended		3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Mar. 20, 2015	Feb. 04, 2015	Mar. 27, 2015	Mar. 30, 2015
Subsequent Event [Line Items]
Proceeds from issuance of common stock	$1,886,000	$15,651,000
Subsequent Events [Member]
Subsequent Event [Line Items]
Common stock, shares issued				200,000	50,000
Proceeds from issuance of common stock					65,000
Number of exchangeable shares under exchange agreement			2,000
Cash consideration for a license fee				$100,000
Stock issued during period, per share price				$1.14
Subsequent Events [Member] | Series A and A1 Preferred Stock [Member]
Subsequent Event [Line Items]
Number of common stock issued upon conversion of preferred stock						8,987,326